i686-apple-darwin11-llvm-gcc-4.2 (GCC) 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2336.1.00)Copyright (C) 2007 Free Software Foundation, Inc.This is free software; see the source for copying conditions. There is NOwarranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

add --gcc=gcc-4.2 or something to configure (after first making sure you have it installed). XC 4.2 does not install it, and prefers llvm-gcc4.2 and clang, which it seems dependancies of Handbrake do not play nice with.

So basically you were missing a dependency - yasm is required to build HandBrake (the ability to build yasm as part of the build process is a recent addition). It's listed in the build instructions on the Wiki and in the doc/ folder in the source.